The invention relates generally to multi-colored epoxy coating compositions and more particularly to a system including one or more base compositions and a set of tinting compositions for coloring the base compositions to yield epoxy coating compositions in a variety of colors.
Multi-colored paint systems are known in which a variety of tinting compositions can be used to custom tint a one component solvent based or water based paint compositions. For example, one can go to a paint store, select a flat, gloss or semi-gloss white base paint and a color from a color chart and by adding specified amounts of tinting compositions from a pre-assembled set, the base paint can be colored to match the color selected from the color chart. However, the same procedure has not existed with respect to two-component epoxy type high solids coatings. As used herein, epoxy materials will be given the ordinary meaning of epoxy in the field, including materials which are applied in a relatively soft or liquid state as a mixed two or more component system, one of the components including ingredients having reactive epoxide groups. Another component is generally referred to as the hardener or activator. Known epoxy resins are made from epichlorohydrin, bisphenol A, bisphenol F or other aliphatic polyols such as glycerol. Such materials can be characterized by a glycidyl ether structure and are commonly cured with a variety of amines and/or amides. The result of the combination of the components is a resin based on the reactivity of such epoxide groups.
In contrast to the virtually unlimited colors which can be achieved from one-component solvent based and water based paint systems, high solids colored epoxy coating compositions tend to be formulated individually, for a specific desired color and not with a versatile base composition which can be tinted as desired. For example, Lee and Neville""s xe2x80x9cHandbook of Epoxy Resinsxe2x80x9d, copyrighted in 1967, Chapter 24, p. 33, describes two formulas for epoxy-coating compositions:
As can be seen, the formulations for these compositions are significantly different. While it is true that the red formulation is characterized as a primer and the green formulation is characterized as an enamel, it is believed that families of colored epoxy coating compositions varying only in pigment selection are heretofore unknown. Moreover, the approach of formulating colored epoxy coating compositions for each specific color has not changed significantly over the past 30-plus years.
For example, referring to a 1992 list of colored coating compositions available from Shell, significant differences can be seen in the black enamel, white enamel and gray enamel formulations. Also, the black formulation instructions call for steel ball mill processing for 48 hours and the white and gray enamel instructions call for high speed dispersing equipment or a sand mill.
One factor which interferes with the ability to provide a standard base and various pigments which can be mixed into the base to change color tones at will, is related to the nature of colored pigments. For example, various data sheets for formulating colored epoxy compositions describe steel ball milling and grinding the ingredients for 48 hours. This is not compatible with a tint-to-order system.
Accordingly, it is desirable to provide a base composition and a set of tinting compositions which can be combined with the base composition to provide epoxy coatings in a rainbow of colors and which overcome other drawbacks or unsatisfactory characteristics of the prior art.
Generally speaking, in accordance with the invention, an epoxy coating base composition and a color system of tinting the composition are provided in which a single base formulation of epoxy coating material can be combined with selected amounts of tinting compositions from one or more tinting sources to provide a selectively colored epoxy coating composition, such as a high solids epoxy coating composition. The base compositions include an uncured epoxy resin. White or white base producing pigments are advantageously added to the resin and ground to a Hegman 6 or smaller. Wetting agents and other additives are also advantageously added. Neutral pigments can be added after the grind. White or light colored pigments are advantageously added to the resin. These can be ground to Hegman 6 or smaller. Wetting agents and other additives are also advantageously added. Neutral pigments are added after the grind. To this, colored pigments can be added as desired to provide a colored composition in a rainbow of colors, based on red, yellow and blue and also black and varied gray tones.
The invention accordingly comprises compositions possessing the characteristics, properties and the relations of components and a system and method involving these compositions, which will be exemplified in the compositions, methods and systems hereinafter described.